A variety of devices for venting surgical casts have been proposed in the past but many of these devices have not met with commercial success. The known devices may have tubes which form air passageways to permit air circulation between the rigid cast exterior and the patient's skin. One such venting device is shown in U.S. Pat. No. 4,898,160, issued Feb. 6, 1990. That device includes a multi-channel, flexible form that is placed adjacent to the skin and is able to adapt to the contour of the body part. Sloping walls of the channels are formed with a plurality of spaced-apart apertures. The venting device can be placed over a cast stockingette, which is first placed on the body part.
In Applicant's U.S. Pat. No. 6,616,622, issued Sep. 9, 2003, a number of different versions of devices for venting surgical casts are described. One version has an elongate, porous woven fabric strip to which are attached a plurality of flexible, elongate tubes with holes distributed along their respective lengths. The strip can be wound around part of a human's body or an animal's body prior to application of the cast. The fabric strip comprises a cotton gauze material.
U.S. Pat. No. 5,916,184, issued Jun. 29, 1999, describes an orthopedic airflow and waterproof cast padding material in the form of an elongate pad with top and bottom surfaces and an inside edge with an overlap region. The pad is made from water and air impermeable material such as thermal foam closed cell polyethylene. This known pad can be helically wrapped around a fractured limb to form a cast pad and an immobilizing waterproof cast when wrapped with special casting tape. A plurality of cushions project from one surface of the elongate pad between the outside edge and the overlap region and these cushions are placed against the skin as the pad is wrapped.